title: Estimation of relative skin sensitizing potency using the local lymph node assay: a comparison of formaldehyde with glutaraldehyde.
abstract: BACKGROUND
  Chemicals vary considerably in their intrinsic ability to cause allergic contact dermatitis. Presently, there are no experimental methods available for the quantitative assessment of the relative sensitizing potency of chemical allergens.
  
  
  OBJECTIVE
  The objective of the investigations described here was to evaluate the use of the local lymph node assay for determining the relative skin sensitizing potential of chemicals. This has been addressed by comparing the sensitizing potency of formaldehyde with glutaraldehyde.
  
  
  METHODS
  Dose responses induced by formaldehyde and glutaraldehyde in the local lymph node assay, using either acetone or dimethylformamide (DMF) as the application vehicle, have been measured. Relative skin sensitizing potency was estimated as a function of the amount of chemical required to induce a threefold increase in lymph node cell proliferative activity, a mathematically derived EC3 value (estimated concentration required to induce a stimulation index of 3).
  
  
  RESULTS
  In both vehicles, glutaraldehyde induced substantially more vigorous responses in the local lymph node assay (EC3 values of 0.006mol/L in acetone and 0.002mol/L in DMF) than did formaldehyde (EC3 values of 0.18mol/L in acetone and 0.11mol/L in DMF).
  
  
  CONCLUSIONS
  These results demonstrate that glutaraldehyde has a considerably greater potential to induce skin sensitization than does formaldehyde; the data are consistent with what is known of the ability of these chemicals to cause allergic contact dermatitis in humans. Using formaldehyde and glutaraldehyde as examples, the results here illustrate the utility of EC3 values derived from local lymph node assay responses for the estimation of the relative potency of skin sensitizing chemicals.
authors.affiliation: Zeneca Central Toxicology Laboratory, Alderley Park, Macclesfield, Cheshire, UK.
authors.forename: J
authors.initials: J
authors.lastname: Hilton
authors.forename: R J
authors.initials: RJ
authors.lastname: Dearman
authors.forename: P
authors.initials: P
authors.lastname: Harvey
authors.forename: P
authors.initials: P
authors.lastname: Evans
authors.forename: D A
authors.initials: DA
authors.lastname: Basketter
authors.forename: I
authors.initials: I
authors.lastname: Kimber
mesh_terms: D000485:Allergens / Q000633:toxicity*; D000818:Animals; D002455:Cell Division; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis / Q000209:etiology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005557:Formaldehyde / Q000633:toxicity*; D005976:Glutaral / Q000633:toxicity*; D008198:Lymph Nodes / Q000187:drug effects* / Q000473:pathology; D051379:Mice
chemical_list: D000485:Allergens; D005557:Formaldehyde; D005976:Glutaral